Firstly, congratulations on your daughters achievements, she sounds like a very gifted and focused musician.
If music is her passion then it would be better for her musicianship if she took part in ensembles and lessons outwith school, and if she does want to pursue a career in music then this is especially important. I have a musical son and he is in a very musical school but his timetable and length of days mean it is actually very difficult for him to put in the instrumental practice required. He boarded for a term and only managed one practice session a week and scraped a grade 3 pass. Two terms on he was a flexi-boarder and he practiced four times a week and gained a grade 5 distinction - I never expected this to happen at a very musical school.
So now I look for schools with shorter days and no Saturday school and am trying to enrich his music through external sources; I think this is especially important when it comes to voice. Does your daughter attend a Junior Conservatoire?
So, I would send her to the school that is closer and gives her more flexibility with her time to join choirs and ensembles outwith school.